Safety switch assembly for a relief valve

ABSTRACT

The within device is concerned with a safety switch for a relief valve which is comprised of mechanical and electrical components. The purpose of the switch is to turn off a boiler when a relief valve fails to function. The relief valve permits excessive steam to be released from the boiler and prevents explosion of the boiler. The within device has a lever arm mounted on a fulcrum. There is a cup at one end of the lever arm. The cup is mounted beneath a pipe which is connected to the relief valve. There is above the lever arm a normally open switch connected to a circuit that controls the flow of a water supply. There is connected below the lever arm another switch which is connected to the energy source that controls the operation of the boiler. When the cup fills up with water from the pipe connected to the deflective relief valve, the weight of the cup will cause the lever arm to tilt on its fulcrum. A normally open switch above the lever arm will be closed by the lever arm to turn off the water supply. The normally closed switch beneath the lever arm will open because of the pressure of the lever arm caused by the water in the cup and the electrical source that operates the controls of the gas or oil burner will be turned off since the circuit will be opened and the source of fuel to the burner will cease to burn.

United States Patent 91 Tria m1 3,818,874 1 June 25,1974

[ SAFETY SWITCH ASSEMBLY FOR A RELIEF VALVE Primary Examiner-Kenneth W. Sprague Attorney, Agent, or Firm-Leonard S. Michelman [57] ABSTRACT The within device is concerned with a safety switch for a relief valve which is comprised of mechanical and electrical components. The purpose of the switch is to turn off a boiler when a relief valve fails to function. The relief valve permits excessive steam to be released from the boiler and prevents explosion of the boiler. The within device has a lever arm mounted on a fulcrum. There is a cup at one end of the lever arm. The cup is mounted beneath a pipe which is connected to the relief valve. There is above the lever arm a normally open switch connected to a circuit that controls the flow of a water supply. There is connected below the lever arm another switch which is connected to the energy source that controls the operation of the boiler. When the cup fills up with water from the pipe connected to the deflective relief valve, the weight of the cup will cause the lever arm to tilt on its fulcrum. A normally open switch above the lever arm will be closed by the lever arm to turn off the water supply. The normally closed switch beneath the lever arm will open because of the pressure of the lever arm caused by the water in the cup and the electrical source that operates the controls of the gas or oil burner will be turned off since the circuit will be opened and the source of fuel to the burner will cease to burn.

10 Claims, 4'Drawing Figures l SAFETY SWITCH ASSEMBLY FOR A RELIEF VALVE This invention is concerned with a safety switch for a relief valve and circuit for closing off the supply of water and the source of energy that operates a boiler at times when the boiler is in a dangerous situation because of the failure of the relief valve to function.

In almost every political community, there are building codes requiring a boiler to have a relief valve, so that the boiler will not explode. The relief valve is designed to open, and permit steam to be released from the boiler, when the pressure of the boiler is at a critical point.

There is no problem when the relief valve is not defective. However, when the relief valve is old, has not been recently tested, or becomes corroded or rusty, if often fails to release and open when the need to do same occurs. There is then a dangerous situation because if the pressure from the boiler is not released, the boiler will blow up. p

This invention is designed to protect the safety of lives and property of people from that crucial moment when the relief valve fails to perfonn.

It is a principal object of the within invention to provide a simple arrangement of component parts in a small light-weight housing that will perform the function of protecting the safety and property of the owner of a boiler when the reliefvalve fails to perform.

It is another object of the within invention to. provide a small, efficient safety device and circuit therefore for protecting against explosions and destruction of a boiler when a relief valve ceases to operate.

It is an additional object of the within invention to provide a safety device for relief valves that is inexpensive in the cost of manufacture and simple to install with an existing boiler.

It is a further object of the within invention to provide a relief valve safety switch which operates in a simple and efficient manner and protects against irreparable damage to property and life.

These and other objects are obtained by the use of a weighted cup which, when filled with a predetermined amount of water, will cause a normallyclosed switch to break a contact and set a circuit into operation. The circuit includes means for the turning off of the flow of 'water to a boiler as well as means for turning off of the energy source, such as electricity and/or gas which ignites the boiler, depending upon whether the boiler is gas operated or oil operated.

For a more detailed description of the within invention, reference is made to the following specification and drawings in which:

FIG. 1 is an exploded diagrammatic front elevational view of the safety switch and circuit with the water supply using low voltage to control the current.

FIG. 2 is a perspective view of the shielded cover of said device.

FIG. 3 is an exploded diagrammatic front elevational view of the device in the circuit with a gas operated boiler with a 1 10-120 volt control circuit.

. FIG. 4 is a diagrammatic view of a safety device lock-the device securely to the structure upon which it is to be supported. It is preferred to be mounted on the boiler itself in a strategic location near the relief valve. Since the general location of the device is not essential but only the connection to the relief valve 4 is important, the details thereof have not been shown in the drawings.

' A water supply 35 passes into the pipe 3. Connected inside the pipe 3 is an electric shut-off valve assembly having a solonoid for operating same 2. Connected to the electric shut-off valve 2 is an electric conductor 12. The conductor 12 is connected to the secondary terminals of the 24-volt transformer 7. The primary side of the 24-volt transformer 7 is connected to a source of 1 10-120 volts at 5 through the conductors 34. The electric shut-off valve 2 has another conductor 13 passing from its other side to the normally open switch 9. The opposite side of the normally open switch 9 is connected to the other terminal of the secondary of the 24- volt transformer 7. There is, therefore, an electrical control circuit running from one terminal of the secondary of the 24-volt transformer 7 through the conductor 12 to the electric solonoid of the shutoff valve 2 and from there to the normally open switch 9 and from the switch 9 back to the other terminal of the secondary of the transformer 7. The normally open switch 9 is operable by the movable arm 25.

The movable arm 25 is in physical contact with and near one end of the lever arm 26.. The lever arm 26 is mounted on a fulcrum 27. (See FIG. I).

1n contact with and on the other side of the fulcrum 27 is a movable arm 28 which operates the normally closed switch 10. There is an opening 29 in the partition 11. The lever arm 26 passes through-the opening 29 and has at the end thereof a cup 31 integral therewith. The cup 31 is located beneath the open pipe 32. The pipe 32 is connected to the relief valve 4 on the opposite side from the boiler. There is a pipe 32a beneath the cup 31 in which the overflow of water from the cup 31 can be carried off so as not to injure the system. Within the box 30 there is a cylinder 8 circumscribing the pipe 32 in which the cup 31 is located. Cylinder 8 acts as a shield to prevent deleterious matter from fall- FIG. 3

Reference is made to the view of FIG. 3. FIG. 3 shows how the basic switch and circuit of FIG. 1 operates to control the turning off of a gas operated boiler.

FIG. 3 is a circuit that is controlled directly by 110-120 volts 5 rather than by the low voltage step down transformer 7 as disclosed in FIG. 1.

In FIG. 3 the electrical source 1 10-120 volts 5 is connected on one side to the conductor 39 through the electric solonoidof shut-off valve 2 which controls the flow of water from the water source 35 through the pipe 3 to the boiler (not shown). The other side of the solonoid shut-off valve is connected to the normally open switch 9 through conductor 1.4. The other side of switch 9 is connected by the conductor 13 to the other side of the electrical source at 5. When switch 9 is closed, current will pass through the solonoid of valve 2 and close the flow of water from the source 35 to the boiler 90.

The other physical structure of the embodiment shown in FIG. 3 is similar to that as shown in FIG. 1.

Connected to the normally closed switch 10 are the electrical conductors 33 and 330. Each one of the conductors 33 and 33a connect to one of each of the sides of the normally closed switch 10 with the thermocouple junction box 16. The thermocouple junction box 16 is conventional and controls the flow of gas to the gas pilot 17.

The operation of FIG. 3 can now be explained. When the relief valve 4 is not functioning properly, water will accumulate in the cup 31 through the pipe 32. When sufficient water is in the cup 31, the weight of cup 31 will cause the lever arm 26 to tilt on the fulcrum 27. When this occurs, the normally open switch 9' will have pressure against it from the weight of the forces on the lever arm 26 causing the normally open switch 9 to close as stated. Immediately valve 2 will close and the water from the source 35 will be blocked off from pipe 3 and the flow of water to the boiler will cease.

At the same time, the normally closed switch at 10 because of the forces applied to the lever arm 26 from the water in the cup 31 will now be opened. This will open the electrical circuit to the thermocouple junction box 16 which feeds the gas to the pilot light 17. Once this circuit opens up, the thermocouple at 16 will close off the flow of gas to the pilot light 17. This will cause the gas operated boiler to cease operation for lack of fuel.

FIG. 4

In FIG. 4 there is a substantially similar arrangement and circuit as in FIGS. 1 and 3. FIG. 4 is designed to control the operation of an oil burner.

The source of water 35 passes through the pipe 3 to the boiler 90 (not shown). A shut-off valve 2 is located within pipe 3 and is controlled by a solonoid assembly 2 within it. The solonoid of valve 2 is in circuit on one side with a source (l l0-l20 volts) of electricity through the conductor'12. The other side of the solonoid of the valve 2 is connected by a conductor 13 to one side of the normally open switch 9. The other. side of the normally open switch 9 is connected by the conductor 14 to the other side of the l l0-l 20 volt source of electricity at 5.

The relief valve 4 of the boiler 90 is connected to a pipe 32 which passes within the housing 1 and into the cylindrical chamber 8.

A lever arm 26 is mounted on a fulcrum 27. Near one end of the arm 26 is located the movable arm 25 to actuate the switch 9, similar to the structure of FIGS. 1 and 3. Likewise, the cup 31 is mounted at the other end of the arm 26 on the other side of the fulcrum 27 through the opening 29 in the partition 11. Again, the cup 31 is located within the cylindrical chamber 8 which guards the cup 31 from filling up with deleterious matter which would cause it to have weight therein and set off the system.

Located between the fulcrum 27 and the cup 31 in movable contact with the lever arm 26 is the switch activating arm 28. A normally closed switch is connected by conductor 33 in an electrical circuit with the limit switch 22. The other side of the limit switch 22 is connected to a source of 220 volts. The other side of switch 10 is connected to the conductor 33a to the other side of the 220 volt source at 19. Connected in series with the switch 10 is the master switch 23. The conductor 41 is connected to conductor 33a and to one side of the master switch 23. The other side of switch 23 is connected by conductor 43 to the oil burner 18. The other side of the oil burner 18 is connected to a conductor 42 which is connected to conductor 33. There is shown a thermostat 21 connected between the limit switch 22 and the heating element 20 in the conventional manner.

In operation, when the relief valve 4 is malfunctioning, water will form in the pipe 32 and cause the cup 31 to fill up. As soon as the weight of cup 31 reaches the critical point, the lever arm 26 will tilt downward from the position of the cup 31 and cause arm 28 to engage switch 10 causing switch 10 to open. Similarly arm 25 will be pushed upward to engage switch 9 which will close.

When stitch 9 closes, an electrical circuit as described will be closed to energize and operate the solonoid of valve 2 shutting off the flow of water from the source 35 in the pipe 3 to the boiler 90.-

When'switch 10 opens, the source 19 of the 220 volts to the burner 18 will be turned off since the circuit through conductors 33 and 33a by way of conductors 41 and 42 to the voltage source 19 will be open instead of closed.

There is also shown in FIG. 4 an arrangement for turning ofi the heating element 20 which heats hot water or may be the source of an electrical heating system. Obviously when switch 10 opens, there will be no flow of current from source 19 through the limit switch 22 and thermostat 21 to the heating element 20. The circuit of FIG. 4 therefore can provide safety not only for an oil operated system but an electrically operated system as well.

I claim:

1. A safety switch assembly for protecting a boiler having a relief valve and an energizing unit to heat said boiler and a circuit for operating the flow of water from a source of water to the boiler, said circuit having a valve therein when the relief valve of the boiler malfunctions comprising a pipe connected to the relief valve,'a lever arm mounted on a fulcrum, means at one end of the lever am for collecting water from the said pipe a nonnally open switch, means connected at the top of the lever arm for operating a normally open switch, said normally open switch connected in a circuit for operating the flow of water to the boiler, means connected at the bottom of said lever arm for operating a normally closed switch, said normally closed switch connected to a circuit for operating the flow of electricity to the boiler energizing unit whereby when said lever arm is pushed downwardly on the fulcrum from the weight of the water that has collected in said means at the end of the lever arm, the normally open switch will close and the circuit in which it is connected will energize said valve and close off the supply of water to the boiler, and whereby the normally closed switch will open and the electrical circuit to operate the energizing unit will cease functioning and the boiler will be turned off.

2. A safety switch assembly for protecting a boiler when the relief valve of the boiler malfunctions as described in claim 1 wherein the circuit of said normally open switch comprises a transformer having a primary and a low voltage secondary, said primary connected to a conventional electrical source, one side of said secondary connected in series with one side of said switch, an electrical solenoid adapted to operate a shut-off valve, said valve for controlling the flow of water from the water supply, the other side of said secondary of transformer connected to one side of said solonoid, the other side of said solonoid connected to the other side of said normally open switch.

3. A safety switch assembly for protecting a boiler when the relief valve of the boiler malfunctions as described in claim 1 wherein the circuit of the normally closed switch comprises a pair of conductors, one conductor of which is connected to one side of said normally closed switch and to one side of the energizing unit, and the other conductor being connected to the other side of said normally closed switch and to the source of electricity.

4. A safety switch assembly for protecting a boiler when the relief valve of the boiler malfunctions as described in claim 2 wherein the circuit of the normally closed switch comprises a pair of conductors, one conductor of which is connected to one side of said normally closed switch and to one side of the energizing unit, and the other conductor being connected to the other side of said normally closed switch and to the source of electricity.

5. A safety switch assembly for protecting a boiler when the relief valve of the boiler malfunctions as described in claim 1 wherein the means for collecting the water comprises a cup-shaped end of the fulcrum, mounted within a dust-free chamber and located beneath a pipe connected to the relief valve.

6. A safety switch assembly for protecting a boiler when the relief valve of the boiler malfunctions as described in claim 2 wherein the means for collecting the water comprises a cup-shaped end of the fulcrum, mounted within a dust-free chamber and located beneath a pipe connected to the relief valve.

7. A safety switch assembly for protecting a boiler when the relief valve of the boiler malfunctions as described in claim 3 wherein the means for collecting the water comprises a cup-shaped end of the fulcrum, mounted within a dust-free chamber and located beneath a pipe connected to the relief valve.

8. A safety switch assembly for protecting a boiler when the relief valve of the boiler malfunctions as described in claim 4 wherein the means for collecting the water comprises a cup-shaped end of the fulcrum, mounted within a dust-free chamber and located beneath a pipe connected to the relief valve.

9. A safety switch assembly for protecting a boiler when the relief valve of the boiler malfunctions as described in claim 5, said dust-free chamber having an opening only large enough to permit the lever arm to move up and down a sufficient distance to operate the norrnallyopen and closed switches, ahd having a pipe run-off means to pennit an overflow of water to escape so as not to injure the device.

10. A safety switch assembly for protecting a boiler when the relief valve of the boiler malfunctions as described in claim 8, said dust-free chamber having an opening only large enough to permit the lever arm to move up and down a sufficient distance to operate the normally open and closed switches, and having a pipe run-off means to permit an overflow of water to escape so as not to injure the device. 

1. A safety switch assembly for protecting a boiler having a relief valve and an energizing unit to heat said boiler and a circuit for operating the flow of water from a source of water to the boiler, said circuit having a valve therein when the relief valve of the boiler malfunctions comprising a pipe connected to the relief valve, a lever arm mounted on a fulcrum, means at one end of the lever arm for collecting water from the said pipe a normally open switch, means connected at the top of the lever arm for operating a normally open switch, said normally open switch connected in a circuit for operating the flow of water to the boiler, means connected at the bottom of said lever arm for operating a normally closed switch, said normally closed switch connected to a circuit for operating the flow of electricity to the boiler energizing unit whereby when said lever arm is pushed downwardly on the fulcrum from the weight of the water that has collected in said means at the end of the lever arm, the normally open switch will close and the circuit in which it is connected will energize said valve and close off the supply of water to the boiler, and whereby the normally closed switch will open and the electrical circuit to operate the energizing unit will cease functioning and the boiler will be turned off.
 2. A safety switch assembly for protecting a boiler when the relief valve of the boiler malfunctions as described in claim 1 wherein the circuit of said normally open switch comprises a transformer having a primary and a low voltage secondary, said primary connected to a conventional electrical source, one side of said secondary connected in series with one side of said switch, an electrical solonoid adapted to operate a shut-off valve, said valve for controlling the flow of water from the water supply, the other side of said secondary of transformer connected to one side of said solonoid, the other side of said solonoid connected to the other side of said normally open switch.
 3. A safety switch assembly for protecting a boiler when the relief valve of the boiler malfunctions as described in claim 1 wherein the circuit of the normally closed switch comprises a pair of conductors, one conductor of which is connected to one side of said normally closed switch and to one side of the enerGizing unit, and the other conductor being connected to the other side of said normally closed switch and to the source of electricity.
 4. A safety switch assembly for protecting a boiler when the relief valve of the boiler malfunctions as described in claim 2 wherein the circuit of the normally closed switch comprises a pair of conductors, one conductor of which is connected to one side of said normally closed switch and to one side of the energizing unit, and the other conductor being connected to the other side of said normally closed switch and to the source of electricity.
 5. A safety switch assembly for protecting a boiler when the relief valve of the boiler malfunctions as described in claim 1 wherein the means for collecting the water comprises a cup-shaped end of the fulcrum, mounted within a dust-free chamber and located beneath a pipe connected to the relief valve.
 6. A safety switch assembly for protecting a boiler when the relief valve of the boiler malfunctions as described in claim 2 wherein the means for collecting the water comprises a cup-shaped end of the fulcrum, mounted within a dust-free chamber and located beneath a pipe connected to the relief valve.
 7. A safety switch assembly for protecting a boiler when the relief valve of the boiler malfunctions as described in claim 3 wherein the means for collecting the water comprises a cup-shaped end of the fulcrum, mounted within a dust-free chamber and located beneath a pipe connected to the relief valve.
 8. A safety switch assembly for protecting a boiler when the relief valve of the boiler malfunctions as described in claim 4 wherein the means for collecting the water comprises a cup-shaped end of the fulcrum, mounted within a dust-free chamber and located beneath a pipe connected to the relief valve.
 9. A safety switch assembly for protecting a boiler when the relief valve of the boiler malfunctions as described in claim 5, said dust-free chamber having an opening only large enough to permit the lever arm to move up and down a sufficient distance to operate the normally open and closed switches, ahd having a pipe run-off means to permit an overflow of water to escape so as not to injure the device.
 10. A safety switch assembly for protecting a boiler when the relief valve of the boiler malfunctions as described in claim 8, said dust-free chamber having an opening only large enough to permit the lever arm to move up and down a sufficient distance to operate the normally open and closed switches, and having a pipe run-off means to permit an overflow of water to escape so as not to injure the device. 